King-Snake Scent Repels Rattlesnakes

CORVALLIS, Ore. - A chemical repellent to ward off rattlesnakes, copperheads and other poisonous vipers may be in the works after some research by scientists at Oregon State and Memphis State universities.

The king snake, a natural enemy of North American pit vipers, gives off a scent that frightens the poisonous snakes, according to Robert Mason, a zoologist at Oregon State, and William Gutzke, a biologist at Memphis State.

Mason and Gutzke say they have isolated the scent and plan to synthesize it for use as a repellent to protect campers, hikers and hunters.

"If you put a line of this substance on the ground, the rattlesnake will not cross it," Gutzke says. "He will turn around and get out of there."

The king snake is non-poisonous and normally harmless to humans and large mammals. But its diet includes poisonous snakes that it constricts, or squeezes to death.

Mason and Gutzke suspected that rattlers and other poisonous snakes used their sense of smell to detect king snakes because even baby rattlers or copperheads that had never seen a king snake fled when it was nearby.

"We humans tend to depend mostly on our senses of sight and hearing," Mason notes. "But smell is more important to animals."

At his laboratory in Corvallis, Mason washed skins shed by king snakes with a strong solvent to extract natural oils known as lipids. Then he began the difficult task of breaking down the lipids into basic chemical compounds.

He and Gutzke then recombined the compounds until they found the right mix to repel the poisonous snakes.